Former Obama cabinet official Julian Castro discusses Trump's border policies and Obama's own record on deportations.

Former Obama cabinet official and top US Democrat Julian Castro has suggested he will "likely" run against US President Donald Trump in the 2020 presidential election.

A former San Antonio mayor and secretary of Housing and Urban Development (HUD) under US President Barack Obama, Castro has been campaigning for Democrats in several states in the run-up to the US 2018 midterm elections.

In his new book, An Unlikely Journey: Waking up from My American Dream, Castro expresses his shock at Trump's election back in November 2016 and is extremely critical of Trump's immigration policy that separated families at the borders.

When challenged about Obama's own record on deportations, Castro responds that "the totality of a record" should be looked at, even though he concedes he was "not comfortable" with how the issue of immigration was handled at the time.

Castro thinks future administrations should avoid "the kind of trauma that the Trump administration is inflicting on these kids" but also "meet the needs of border security".

In this special interview, Julian Castro shares his vision for the future of the Democratic Party in an age of Trump.